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Tuesday, 23 August 2011

I'm slowly working my way through Olaf Sporn's excellent book, Networks of the Mind. The purpose of this book is to introduce neuroscientists to network theory, and vice versa; I'm eavesdropping and tooling up on both. It's slow going only because it's pretty much all new territory to me, but I'm seeing a lot of potential in the overall approach to the brain, and this just confirms for me that Sporns understands what he does pretty deeply.

Fact: in the digestive tract of the lobster, its nervous system can have
100k-200k different neural states that produce the same behavior

This struck me as an astonishing fact; to my mind, it throws the idea that hunting for the neural correlates of behaviour into serious doubt. At the very least, it needs to radically change what you expect to find. I finally found the reference for this fact in Sporns' book (Prinz, Bucher & Marder, 2004; download), and Sporns has some interesting context for this fact (which Hood undersells - see below) and why it's interesting, rather than soul-crushingly depressing. There are some interesting potential consequences relevant to my current ponderings on the brain, although it's definitely still at the 'these sound like the same sort of principle' level of analysis.

Tuesday, 16 August 2011

The other day, psychologist Tom Hartleytweeted "Your reflection is always half the size of the real thing - no matter how far from mirror. Hard to believe but true." and linked to this post in which someone demonstrates this effect. I had never quite thought about it, but realised it was of course always true: the mirror is at half the distance specified in the reflection. Then I read this post linked from the original, which reviewed an article by Lawson et al (2007) describing how people misjudge the size of objects on mirrors - specifically, they think the projection is larger than it actually is. This got me thinking about some work by Gibson on slant perception (Gibson, 1950) and then I realised that this really is an interesting topic. So I'm taking a break from the brain this week to blog about some optics instead.

Friday, 12 August 2011

As Andrew has been tackling a new job description for the brain (part 1 and part 2), several comments have been made that suggest that his approach (and the ecological stance in general) might be fine for perception/action, but not for other types of tasks/behaviours. Later on in this post I also think about how we might be able to distinguish between association and direct access to meaning, which is another idea that has been coming up repeatedly in the comments (see here).

In this post I want to think about what makes perception different from conception (Andrew reviews William James' views on this distinction here). I will argue that both occur as networks of evolving neural activity (with perception, this network extends to the environment and the body), but these networks have different properties because they are driven by signals of differential stability. I do not think it is accurate to think of perception as something that happens in V1, for example, and conception as something that happens in SFG. If parts of the brain reverberate in a system along with parts of the brain that are directly interfacing with an energy array in the environment, it seems correct to refer to that whole system as perception. In contrast, if a network of activity appears to be relatively encapsulated with respect to external energy arrays, it seems correct to refer to that system as an act of conception. For now I will leave aside the problem of how conceptual networks develop, but I hope to return to this later.

Tuesday, 9 August 2011

One of the problems I face as I try to figure out what the brain is up to, if not representing, is that I can't rely on the neuroscience literature to back me up. The problem is that, while there has been a lot of data collected over the years, very little of it has been collected within an ecological framework. Neuroscientists are looking for how the brain represents information, not how it perceives it; they're looking to see where perception and action are integrated in the brain, not how the brain-body-environment system produces stable, functional behaviour. This matters because there's no such thing as theory-free observations - all data comes from this experiment rather than that experiment, and even simply reporting a result is laden with theoretical assumptions, even when these aren't explicitly identified. So until I can find a neuroscientist interested in collecting a little data (and I would love to hear from any such person!) I'm limited to laying out the consequences of taking the ecological route and critiquing what's out there already.

The worst offenders, in terms of theory-laden data disguised as 'merely the observed facts', are mirror neurons. They are, I think, the text book example of what's the matter with neuroscience, and I thought it was about time to talk about them a little. For those interested, the most recent exposition of what mirror neurons are and do can be found in a recent (and currently open access) issue of Perspectives on Psychological Science: there's a brief introduction (Glenberg, 2011a), a detailed Q&A paper (Gallese et al, 2011) by five main figures in the field, and a summary (Glenberg, 2011b).(Update: recent meta analysis finds mirror type activity all over the brain, including the cerebellum!)

Tuesday, 2 August 2011

I want to continue thinking about the implications of the claim that the brain does not trade in representations. I'm not looking to defend this view here; we got into it a bit last time, I've talked about it here, and if you can't imagine what cognition without representation might look like, then you should read this post by Sabrina and then Radical Embodied Cognitive Science before worrying me with your lack of imagination. If you then feel like getting into it, Sabrina is tackling this topic in detail, beginning here.

If the brain isn't mentally representing, what is it doing? Last time, I got into the idea that the brain is part of a embodied cognitive system. It's in the middle of a rich information flow, with access to perceptual information about the world and ourselves, and it's a critical part of the action system, involved in our responses to that information. I talked about it as the fast response system in the set of inherent dynamical resources available for us to use to form task specific devices; I want to expand on that a little.